package com.kevin.single;

import com.kevin.list.AbstractList;

/**
 * @Author LXL
 * @Date 2020/9/26 17:28
 **/
public class LinkedList<E> extends AbstractList<E> {

    private Node<E> first;

    private static class Node<E>{
        private E element;
        private Node<E> next;

        public Node(E element, Node next){
            this.element = element;
            this.next = next;
        }
    }
    @Override
    public void clear() {
        size = 0;
        first = null;
    }

    @Override
    public E get(int index) {
        return node(index).element;
    }

    @Override
    public E set(int index, E element) {
        Node<E> node = node(index);
        E oldElment = node.element;
        node.element = element;
        return oldElment;
    }

    @Override
    public void add(int index, E element) {
        rangeCheckForAdd(index);

        if (index == 0){
            first =  new Node<>(element, first);
        }else {
            Node<E> prev = node(index - 1);
            prev.next = new Node<>(element, prev.next);
        }
        size++;
    }

    @Override
    public E remove(int index) {
        rangeCheck(index);
        Node<E> node = first;
        if (index == 0){
            first = first.next;
        }else {
            Node<E> prev = node(index - 1);
            node = prev.next;
            prev.next = node.next;
        }
        size--;
        return node.element;
    }

    @Override
    public int indexOf(E element) {
        if (element == null) {
            Node<E> node = first;
            for (int i = 0; i < size ; i ++){
                if (node.element == null){
                    return i;
                }
                node = node.next;
            }
        }else {
            Node<E> node = first;
            for (int i = 0; i < size ; i ++){
                if (element.equals(node.element)){
                    return i;
                }
                node = node.next;
            }
        }
        return ELEMENT_NOT_FOUND;
    }

    private Node<E> node(Integer index){
        rangeCheck(index);

        Node<E> node = first;
        for (int i = 0; i< index ; i++){
            node = node.next;
        }

        return node;
    }

    @Override
    public String toString() {
        StringBuilder string = new StringBuilder();
        string.append("size=").append(size).append(", [");
        Node<E> node = first;
        for (int i = 0; i < size ; i ++){
            if (i != 0) {
                string.append(", ");
            }
            string.append(node.element);
           node = node.next;
        }
        string.append("]");
        return string.toString();
    }
}
